Piston for internal-combustion engines



March 9 H9260 3,575,751

L. FOX

PISTON FOR INTERNAL COMBUSTION ENGINES Filed Nov. 9, 11923 Q INVENTOR. 64w do 4 M AT] GRNEY.

. Patented Mar. 9, 1926.

UNITED STATES PATENT OFFICE.

LEE FOX, or ROCK ISLAND, ILLINOIS.

PISTON ron INTERNAL-COMBUSTION nnemns.

Application filed November 9, 1923. Serial No. 673,734.

' piston slap is largely done away with, and

the scoring of the walls ofthe cylinder is prevented. This is accomplished by the production of a piston having aflexible skirt portion which will'readily adapt itself to the cylinder walls, so as to compensate for any possible wear thereof. A wider contact surface between the piston and cylinder results, so that the forceofthe piston stroke is distributed more generally over the surface of the cylinder wall.

Another urpose of the invention is the provision 0 an auxiliary supporting device for the piston skirt, which will automatically assist in holding the same to its work.

The construction and operation is such that the piston can be placed in a' cylinder the walls of which have been badly scored,

and are out of round, and adjust itself er-' fectly thereto, so that the operation wil be as perfect as when the cylinder was new.

As a consequence there is no rocking of the piston in its movement, and accompanying piston slap which is so common in worn cylinders. The compensating action of the piston is exerted throughout the length of the skirt, the piston being so constructed as to allow the greatest amount of expansion at the sides 'of the cylinder wall where the greatest wear usually occurs. The perfect fitting of the piston also prevents pum ing of the cylinder oil past the piston, an assists in keeping the cylinder head free from carbon. This results in a considerable saving of cylinder oil. By this construction it is also possible to omit what is known as the \vipin ring of the piston, the chief purpose 0 which is to prevent the oil from finding its way into the head of the cylinder.

Another purpose of the invention is to plrovide a uniform working contact between tie lengt 1 of the cylin er, so that there will not piston and c linder, throughout the be an inordinate amountof pressure exerted upon a certain part of the cylinder, as is now usually the case.

Another purpose thereof is the formation'of a piston which will not have to be provided with depressions-about the wristpin bosses, to allow for the expansion-of the piston when in operation, but which will automatically take care of any such expansions This permits of a contact between the piston and cylinder wall throughout the entire length of the skirt of the piston. Z

The above named, and other features and advantages of the invention,'will more fully appear from the following specification, reference being had to the accompanying drawings, in which:

Fig. 1 is a longitudinal a iston embodying thev invention.

ig. 2-is an elevation thereof.

medial section of Fig. 3 is a similar view with the piston in position at right angles to the position shown in Fig. 2.

The reference number 1 indicates the head' of a piston, and 2 the skirt thereoflthe head bemg formed with the usual annular'channels 3, to receive piston rings 4. In opposite sides of the piston are wrist-pin" bosses 5, with openings to receive the ends of the wrist-pin. Extending longitudinally of the skirt to the lower ed thereof are pairs of slots 6 and 7, prefera ly disposed in a diag- 'onal direction with reference to the axial line of the piston. The slots 6 are on opposite sides 0 the wrist-pin openings, and com verge downwardly, as shown in Fig. 2, while the slots 7 are formed in the side spaces on the skirt, and diverge downwardly to' the edge thereof. The slots 6 form tongues 8 which are broadest at their upper ends,;'and form supports, for the bosses 5, while the slots 7 embrace sectional portions 9, which are narrowest at their attached ends,j and therefore possess a relatively greater amount of resiliency.- These sections 9, the edges of which are designed to embraceone-half or more of the circumference of the end of the skirt 2, are on sides of the piston alternating with the sections 8, which sup ort the wristpin bosses, and the sections 9 t erefore'operate on the walls of the-cylinder where the greatest wear is likely to occur. These sec-' tions, with their limited attachment to the piston head, readily adapt themselves to the shape of the cylinder. The slots extend to a point near the shoulder of the p1ston,.and

the diagonal disposition of such slots assists in removing surplus oil from the wall of the Cylinder, and conveying it to the interior of the piston.

The diameter of the head portion of the piston is slightly less than that of the skirt, as is usual in devices of this kind, but in the present invention there is a gradual increase in diameter from the head to the lower end of the skirt, the diameter of which is somewhat greater than that of the bore of the cylinder in whichthe piston is to operate. in order to position the piston in the cylinder, it is necessary to compress the skirt of such piston until the diameter thereof is sufficiently reduced to enable the same to be inserted in the end of the cylinder. The outward tension of the skirt sections, after the piston is in position, will then operate to hold such skirt in close working engagement with the wall of the cylinder, separated therefrom only by a thin film of oil. This film is maintained by reason of all surplus oil being, forced downwardly and away from the cylinder wall by the lower edge of the piston, in its downward movement.

The displacement of the sections 01 the piston skirt inwardly is prevented by means of an expansion ring 10, supported on the in ner face of the skirt between annular ribs 11 and 12 projected from said face. Said ring is split at one of its sides and possesses an outward tension which assists in holding the skirt sections in operative positions.

The diameter at the upper end of the skirt of the piston is substantially the same as that of the bore of the cylinder, so that when the engine is in operation, practically the entire skirt of the piston is in working contact with the wall of the cylinder. This results in a smoother operation, and without causing a wear of the cylinder at any particular part. In case there is any wear of the cylinder or piston, this is compensated for by the resiliency of the piston sections, which tends to hold the same outwardly under all conditions.

On accountof the greater amount of material in the wrist-pin bosses there is a tendcncy of greater expansion at those points, making it necessary to reduce the thickness of the piston walls at those points, as hereinbetore mentioned, but that is not necessary in the present construction, as the slots 6 provide for this extra amount of expansion.

What I claim, and desire to secure by Letters Patent, is:

A piston, comprising a head, and a skirt provided with wrist-pin bosses, and having longitudinal slots on opposite sides of said bosses, extending to the open end of said skirt, and converging in that direction, so that the sides of the piston receiving the connecting rod thrust will have greater eX- pansible capacity than the other sides thereof.

In testimony whereof I ailix my signature.

LEE FOX. 

